Elevated Temperature Erosion Resistance of Several Experimental Amorphous Thermal Spray Coatings

Author(s):  
B. Wang

Abstract The elevated temperature erosion resistance of experimental amorphous thermal spray coatings was determined in a laboratory elevated temperature erosion tester. Test conditions attempted to simulate the erosion conditions found at the combustor waterwall tubes in fossil fuel fired boilers. Erosion tests were conducted on four experimental amorphous thermal spray coatings, using the bed ash retrieved from an operating coal fired boiler. An experimental arcspray process was used to spray coatings. These results were compared with erosion test results of two common structural materials, two commercially available arc-sprayed coatings, and a proprietary HVOF coating. Test results indicated that the Duocor coating had the highest erosion resistance among the four experimental coatings, it showed equal resistance to the HVOF coating (DS-200). Compared to AISI 1018 steel, both Duocor and DS-200 coatings reduced material wastage by 26-fold. Other test results indicated that the XJ-16, 60T and Armacor M coatings had equal erosion resistance reducing material wastage approximately 7-fold, while Arrnacor CW reduced by IO-fold. Only slightly better than the unprotected 1018 steel, the X-20 coating performed poorly on erosion tests. The high erosion resistance of Duocor and DS-200 coatings was attributed to their high densities and fine splat structures.

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Vineet Shibe ◽  
Vikas Chawla

Thermal spray coatings can be applied economically on machine parts to enhance their requisite surface properties like wear, corrosion, erosion resistance, and so forth. Detonation gun (D-Gun) thermal spray coatings can be applied on the surface of carbon steels to improve their wear resistance. In the present study, alloy powder cermet coatings WC-12% Co and Cr3C2-25% NiCr have been deposited on ASTM A36 steel with D-Gun thermal spray technique. Sliding wear behavior of uncoated ASTM A36 steel and D-Gun sprayed WC-12% Co and Cr3C2-25% NiCr coatings on base material is observed on a Pin-On-Disc Wear Tester. Sliding wear performance of WC-12% Co coating is found to be better than the Cr3C2-25% NiCr coating. Wear performance of both these cermet coatings is found to be better than uncoated ASTM A36 steel. Thermally sprayed WC-12% Co and Cr3C2-25% NiCr cermet coatings using D-Gun thermal spray technique is found to be very useful in improving the sliding wear resistance of ASTM A36 steel.


2000 ◽  
Author(s):  
Christian Moreau ◽  
Luc Leblanc

Abstract Thermal spray coatings are used to protect surfaces against exposure to severe conditions. To insure a reliable protection, not only the structure and properties of the sprayed coatings must be optimized but also one needs to develop appropriate process control techniques to produce high performance coatings in a consistent manner, day after day. This is particularly important during plasma spraying as the wear of the electrodes affects significantly the plasma characteristics and consequently the coating properties. First, in this paper, the stability of plasma spray processes is investigated by monitoring in-flight particle characteristics and plasma fluctuations. Secondly, the possibility and advantages of controlling plasma spray processes by monitoring and regulating the condition of the sprayed particles are discussed. Finally, we will see how the properties of thermal barrier coatings and wear resistant coatings can be optimized by controlling the temperature and velocity of the sprayed particles both in the plasma spray and HVOF (high velocity oxy-fuel) processes.


Author(s):  
R.C. Tucker ◽  
A.A. Ashari

Abstract Thermal spray coatings are widely used for erosion resistance, but the relationship between the microstructure of the coatings and their erosion resistance is not well understood. In this paper the performance of several commonly used coatings at ambient and elevated temperatures is reviewed in light of the coatings' structure and compared with a new coating. Two high temperature industrial applications, solid particle erosion in steam turbines and alumina-based erosion have been chosen to illustrate the significance of a coating's structure on its performance.


2011 ◽  
Vol 696 ◽  
pp. 314-317
Author(s):  
Toshinari Okagaito ◽  
Yuji Fukuda ◽  
Yoshitaka Kojima

Fe-Si intermetallic thermal spray powders have been developed for sulfidation corrosion and erosion protection for furnace walls in pulverized coal fired boiler. In this paper, evaluation of corrosion and erosion resistance of developed coatings was performed. The corrosion test results showed that the developed coatings almost equal corrosion resistance to conventional corrosion resistant coatings under the low NOX boiler condition. Erosion test results also indicated that Fe-20Si-1B using atmospheric plasma spraying showed higher erosion resistance than the conventional coatings.


Author(s):  
J. Gutleber ◽  
S. Sampath ◽  
S. Usmani

Abstract The erosion behavior of yttria stabilized zirconia thermal barrier coatings is investigated with respect to powder particle size. Solid particle erosion experiments were conducted at room temperature to determine the mechanism of erosion for ceramic thermal spray coatings. Testing was carried out on as-sprayed as well as thermally cycled specimens. Porosity and bend testing measurements indicate that a decrease in porosity and an increase in inter-lamellar strength leads to an increase in the erosion resistance of ceramic thermal spray coatings.


Author(s):  
John Henao ◽  
Carlos A. Poblano-Salas ◽  
Fabio Vargas ◽  
Astrid L. Giraldo-Betancur ◽  
Jorge Corona-Castuera ◽  
...  

The goal of the chapter is to address the fundamental theory of thermal spraying and its modern industrial applications, in particular, those involving flame spray, HVOF, plasma spray, and cold spray processes. During the last 30 years, thousands of manuscripts and various book chapters have been published in the field of thermal spray, displaying the evolution of thermally sprayed coatings in many industrial applications. Thermal spray coatings are currently interesting for different modern applications including prosthesis, thermal barriers, electrochemical catalysis, electrochemical energy conversion devices, biofouling, and self-repairing surfaces. The chapter will explain the fundamental principles of the aforementioned thermal spraying processes and discuss the effect of different controlling parameters on the final properties of the produced coatings. This chapter will also explore current and future industrial applications of thermal spray coatings.


Author(s):  
Harpreet Singh Grewal ◽  
Harpreet Singh

Slurry erosion is a degrading phenomenon usually observed in machineries dealing with particle-laden fluid such as hydro power plants, ship propellers, pump impellers, valves, and connecting pipes. The low erosion resistance of commonly employed structural materials prompts the use of different surface modification techniques. Among several types of surface modification techniques, thermal spraying has achieved a significant recognition worldwide due to its versatile nature. In this chapter, slurry erosion behavior of thermal sprayed coatings has been discussed with special emphasis on the contribution of different coating related parameter. It has been observed that microstructure play an important role in determining the slurry erosion performance of thermal spray coatings. Different microstructural features such as splat boundaries, pores, un-melted particles, and cracks are detrimental for the thermal spray coatings exposed to erosive environment. A parameter useful for identification of primary erosion mechanism for thermal sprayed coatings is also discussed.


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